1) The world's first car radio was invented in 1929.

2) The ancient city of Athens, Greece, is often considered the birthplace of democracy, where citizens had a say in the decision-making process.

3) The world's most expensive car is the Bugatti La Voiture Noire, which sold for over $18 million.

4) The world's largest volcano, Mauna Loa in Hawaii, is also one of the most active. It stands over 13,000 feet (4,000 meters) above sea level.